Flexible channel coordination for multiple optical carrier optical networks

ABSTRACT

One or more management systems coordinate wavelength configuration patterns of a plurality of multi-wavelength optical transport nodes in an optical network for a first transport period. The one or more management systems determine data traffic demand changes in the optical network; and coordinate wavelength configuration patterns of the plurality of multi-wavelength optical transport nodes in the optical network for a second transport period, that is subsequent to the first transport period, based on the determined data traffic demand changes.

RELATED APPLICATION

The present application claims priority from U.S. application Ser. No.14/283,588, filed May 21, 2014, the contents of which are herebyincorporated by reference herein in their entirety.

BACKGROUND

Optical networks employing 10 gigabit Ethernet (10GE) transport Ethernetframes at a rate of 10 gigabits per second. A router in such an opticalnetwork typically includes multiple client interfaces, each of whichuses a single optical carrier (e.g., light of a single wavelength) forreceiving and/or transmitting data. Transport equipment connects to therouter via multiple client interfaces, which each use the single opticalcarrier, to receive data transmitted from the client interfaces of therouter. The transport equipment may further include multiple transportcards, each of which transmits outgoing data over a single opticalcarrier. The transport equipment sends the data via the single opticalcarriers to destination transport nodes in the optical network.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram that depicts an exemplary network environment inwhich flexible channel coordination may be implemented in a multipleoptical carrier optical network;

FIG. 2 is a diagram that depicts exemplary optical transport nodes ofthe optical network of FIG. 1;

FIG. 3 is a diagram that depicts exemplary components of a device thatmay correspond to either, or both, of the router management systemand/or the transport card/Reconfigurable Optical Add/Drop Multiplexermanagement system of FIG. 1;

FIG. 4 is a diagram that illustrates a Reconfigurable Optical Add/DropMultiplexer of FIG. 1 according to an exemplary implementation;

FIGS. 5 and 6 are diagrams that depict examples of flexible channelcoordination of the optical transport nodes of FIG. 2 during twodifferent transport periods;

FIGS. 7A and 7B are flow diagrams that illustrate an exemplary processfor flexible channel coordination during optical transport in thenetwork environment of FIG. 1; and

FIGS. 8 and 9 are diagrams that depict examples of channel coordinationamong multiple optical transport nodes during two different transportperiods.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description refers to the accompanying drawings.The same reference numbers in different drawings may identify the sameor similar elements. The following detailed description does not limitthe invention.

FIG. 1 is a diagram that depicts an exemplary network environment 100 inwhich flexible channel coordination may be implemented for a multipleoptical carrier optical network. As shown, network environment 100 mayinclude a multiple optical carrier optical network 105, a routermanagement system 110, and a transport card/Reconfigurable OpticalAdd/Drop Multiplexer (ROADM) management system 115. In oneimplementation, the multiple optical carriers of optical network 105 mayinclude light of multiple different wavelengths, such as multiplewavelengths λ₁ through λ_(n) (where n is an integer greater than orequal to 2).

Multiple carrier optical network 105 may include multiple transportnodes, such as transport nodes 120-A, 120-B and 120-C (individually andgenerically referred to herein as a “transport node 120”) depicted inFIG. 1, for routing, switching and transporting data traffic viamultiple different optical carriers (e.g., wavelengths). Transport nodes120-A, 120-B and 120-C are shown merely for purposes ofillustration—optical network 105 may include other transport nodes inaddition to transport nodes 120-A, 120-B and 120-C. As shown, transportnode 120-A may include a router 125-A, transport equipment 130-A andROADM 135-A. Transport node 120-B may include a router 125-B, transportequipment 120-B, and ROADM 135-B. Transport node 120-C may include arouter 125-C (routers 125-A, 125-B and 125-C individually andgenerically referred to herein as “router 125”), transport equipment130-C (transport equipment 130-A, 130-B and 130-C individually andgenerically referred to herein as “transport equipment 130”), and ROADM135-C (ROADM 135-A, 135-B and 135-C individually and genericallyreferred to herein as “ROADM 135”). Transport nodes 120 of opticalnetwork 105 may be interconnected via optical fibers, with each opticalfiber carrying optical signals via one or more optical carriers (e.g.,wavelengths). Transport nodes 120 may additionally connect to datatraffic source or destination end nodes (not shown in FIG. 1) viaoptical fibers and/or electrical cables (e.g., coaxial cables).

Each router 125 may receive data traffic, either via electrical oroptical transmission, and may use routing algorithms for routing thedata traffic towards its destination as multiple optical carrier (e.g.,multiple wavelength) optical signals via multiple client interfaces.Each router 125 may additionally queue, route and switch the receiveddata traffic based on instructions received from router managementsystem 110, as further described below. Each transport equipment 130 mayinclude, as described further below with respect to FIG. 2, multipleclient interfaces for receiving data traffic via multiple opticalcarrier optical signals, and multiple transport cards for transmittingthe data traffic via multiple optical carrier optical signals to arespective ROADM 135. Each transport equipment 130 may receive andtransmit the data traffic via the multi-wavelength optical signals basedon instructions from transport card/ROADM management system 115, asfurther described below.

Each ROADM 135 may include any type of ROADM for multiplexing anddemultiplexing data traffic carried via multiple optical carriers (e.g.,multiple wavelengths. Each ROADM 135 may include, for example, a PlanarLightwave Circuit (PLC), a Wavelength Selective Switch (WSS) or aWavelength Crossconnect (WXC) ROADM. Each ROADM 135 may multiplex ordemultiplex the data traffic via the multiple optical carrier opticalsignals based on instructions from transport card/ROADM managementsystem 115, as further described below.

Router management system 110 may include one or more network devices(e.g., depicted in FIG. 3) that provide instructions to the routers 125of the transport nodes 120 of optical network 105 for controlling thequeueing, routing and switching of data flows of the data traffic fortransport by transport equipment 130 via multiple optical carriers(e.g., wavelengths). Router management system 110 may connect to routers125 of transport nodes 120 of optical network 105 via, for example, oneor more networks (not shown in FIG. 1) that are different from opticalnetwork 105. For example, the one or more different networks may includeone or more of a Public Switched Telephone Network (PSTN), a wirelessnetwork, a local area network (LAN), a wide area network (WAN), ametropolitan area network (MAN), an intranet, or the Internet. Thewireless network may include a satellite network, a Public Land MobileNetwork (PLMN), or a wireless LAN or WAN (e.g., Wi-Fi). Routermanagement system 110 is depicted with a connection to each of router A125-A, router B 125-B, and router C 125-C.

Transport card/ROADM management system 115 may include one or morenetwork devices (e.g., depicted in FIG. 3) that provide instructions totransport equipment 130 and ROADMs 135 of transport nodes 120 of opticalnetwork 105 for configuring optical carrier configuration patterns forsending and receiving data traffic via multiple optical carrier (e.g.,multiple wavelength) optical signals over multiple optical fibers. Eachoptical carrier configuration pattern may include, for example, multipleoptical wavelengths having certain switched paths from a transport cardthrough a ROADM to one or more destination transport nodes. Therefore,in one implementation, a change in optical carrier configurationpatterns may include changing from a first wavelength configurationpattern that includes multiple optical wavelengths having first switchedpaths through a ROADM to the one or more destination transport nodes, toa second wavelength configuration pattern that includes the multipleoptical wavelengths having second switched paths through the ROADM tothe one or more destination transport nodes, where at least one of thesecond switched paths is different from at least one of the firstswitched paths. Transport card/ROADM management system 115 is depictedwith a connection to each of transport equipment A 130-A, ROADM A 135-A,transport equipment B 130-B, ROADM B 135-B, transport equipment C 130-Cand ROADM C 135-C (with the connective links between system 115 andtransport equipment C 130-C and ROADM C 135-C shown passing behindtransport node 120-B).

The configuration of components of network environment 100 illustratedin FIG. 1 is for illustrative purposes. Other configurations may beimplemented. Therefore, network environment 100 may include additional,fewer and/or different components that may be configured in a differentarrangement from that depicted in FIG. 1. For example, networkenvironment 100 may include numerous transport nodes 120. Additionally,router management system 110 and transport card/ROADM management system115 are depicted as separate network devices. In other implementations,router management system 110 and transport card/ROADM management systemmay be implemented together within a single network device.

FIG. 2 is a diagram that depicts exemplary transport nodes 120-A, 120-Band 120-C of multi-wavelength optical network 105 of FIG. 1. As shown,transport node 120-A may include router A 125-A, transport equipment A130-A, and ROADM A 135-A. Router A 125-A may have multiple clientinterfaces 140-A₁ through 140-A_(p) (where p is an integer greater thanor equal to 2). Transport equipment A 130-A may have multiple clientinterfaces 145-A₁ through 145-A_(p) and multiple transport cards 150-A₁through 150-A_(p). Each client interface and transport card of router125-A and transport equipment 130-A transports multiple optical carriers(e.g., wavelengths λ₁ through λ_(n)). Transport nodes 120-B and 120-Cmay each be similarly configured, with similar components, to transportnode 120-A. FIG. 2 depicts transport node 120-B as including ROADM B135-B, transport equipment B 130-B, and router B 125-B. For purposes ofsimplicity, transport equipment B 130-B is shown as including only asingle transport card 150-B₁ and only a single client interface 145-B₁,and router B 125-B is shown as including only a single client interface140-B₁. FIG. 2 further depicts transport node 120-C as including ROADM C135-C, transport equipment C 130-C, and router C 125-C. Again, forpurposes of simplicity, transport equipment C 130-C is shown as onlyincluding a single transport card 150-C₁ and only a single clientinterface 145-C₁, and router C 125-C is shown as only including a singleclient interface 140-C₁. Transport equipment B 130-B and transportequipment C 130-C may each include multiple transport cards 150 andmultiple client interfaces 145, and router B 125-B and router C 125-Cmay each include multiple client interfaces 140 similar to thosedepicted for transport node 120-A.

In the single direction of data traffic transmission shown in FIG. 2,incoming data traffic is routed by router 125-A for transmission atclient interfaces 140-A₁ through 140-A_(p) towards a destinationtransport node. Client interfaces 140-A₁ through 140-A_(p) may includeinterface circuitry and optical components for transmitting the datatraffic as optical signals via multiple different optical carriers(e.g., wavelengths λ₁-λ_(n)). For example, if router A 125-A supports 8different optical wavelengths (n=8), then each of client interfaces140-A₁ through 140-A_(p) may transmit optical signals via the 8different optical wavelengths.

Client interfaces 145-A₁ through 145-A_(p) of transport equipment A130-A may include optical components and circuitry for receiving theoptical signals, via multiple different optical carriers (e.g.,wavelengths), from a respective client interface 140 of router A 125-Aand may convert the optical signals to electrical signals. Clientinterfaces 145-A₁ through 145-A_(p) of transport equipment A 130-A maysupply the electrical signals to respective ones of transport cards150-A₁ through 150-A_(p). Transport cards 150-A₁ through 150-A_(p) mayinclude circuitry and optical components for converting the electricalsignals, corresponding to the data traffic, to optical signalstransmitted via one or more optical carriers (e.g., wavelengths) ofmultiple optical carriers, and for transmitting the optical signals toROADM A 135-A. ROADM A 135-A may, based on switching controlinstructions received from system 115 (not shown in FIG. 2), selectivelyswitch each optical carrier (e.g., wavelength) carrying optical signalscorresponding to the data traffic on outgoing optical fibers todestination transport node 120-B or transport node 120-C. In the exampledepicted in FIG. 2, ROADM A 135-A is shown as transmitting opticalsignals via optical wavelengths λ₁-λ_(n) on optical fibers to transportnode 120-B, and ROADM A 135-A is further shown as transmitting opticalsignals via optical wavelengths λ₁-λ_(n) on optical fibers to transportnode 120-C.

Upon receipt of the optical signals, via n different optical carriers(e.g., wavelengths), at transport node 120-B, ROADM B 135-B switches thesignals to transport card 150-B₁. Transport card 150-B₁ includes opticalcomponents and circuitry for receiving the optical signals, via the ndifferent optical carriers (e.g., wavelengths), from ROADM B 135-B,converts the optical signals to electrical signals, and supplies theelectrical signals to client interface 145-B₁.

Client interface 145-B₁ of transport equipment B 130-B may includecircuitry and optical components for receiving the electrical signals,and converting the electrical signals to optical signals, correspondingto the data traffic, for transmission to client interface 140-B₁ ofrouter B 125-B. Router B 125-B may receive the optical signals asoutgoing data traffic, and may, based on existing routing algorithms andalso based on instructions from system 110, queue, route and/or switchthe data traffic to an outgoing client interface (not shown) fortransmission to a next transport node, or to a network endpoint.

Upon receipt of the optical signals, via n different optical carriers(e.g., wavelengths), at transport node 120-C, ROADM B 135-C switches thesignals to transport card 150-C₁. Transport card 150-C₁ includes opticalcomponents and circuitry for receiving the optical signals, via the ndifferent optical carriers (e.g., wavelengths), from ROADM C 135-C,converts the optical signals to electrical signals, and supplies theelectrical signals to client interface 145-C₁.

Client interface 145-C₁ of transport equipment C 130-C may includecircuitry and optical components for receiving the electrical signals,and converting the electrical signals to optical signals, correspondingto the data traffic, for transmission to client interface 140-C₁ ofrouter C 125-C. Router C 125-C may receive the optical signals asoutgoing data traffic, and may, based on existing routing algorithms andalso based on instructions from system 110, queue, route and/or switchthe data traffic to an outgoing client interface (not shown) fortransmission to a next transport node, or to a network endpoint.

FIG. 3 is a diagram that depicts exemplary components of a device 300.Router management system 110 and transport card/ROADM management system115 may each have the same or similar components in a same or similarconfiguration to that of device 300 shown in FIG. 3. Device 300 mayinclude a bus 310, a processing unit 320, a main memory 330, a read onlymemory (ROM) 340, a storage device 350, an input device(s) 360, anoutput device(s) 370, and a communication interface(s) 380. Bus 310 mayinclude a path that permits communication among the elements of device300.

Processing unit 320 may include one or more processors ormicroprocessors, or processing logic, which may interpret and executeinstructions. Main memory 330 may include a random access memory (RAM)or another type of dynamic storage device that may store information andinstructions for execution by processing unit 320. Read Only Memory(ROM) 340 may include a ROM device or another type of static storagedevice that may store static information and instructions for use byprocessing unit 320. Storage device 350 may include a magnetic and/oroptical recording medium. Main memory 330, ROM 340 and storage device350 may each be referred to herein as a “tangible non-transitorycomputer-readable medium.”

Input device 360 may include one or more mechanisms that permit anoperator (or user) to input information to device 300, such as, forexample, a keypad or a keyboard, a display with a touch sensitive panel,voice recognition and/or biometric mechanisms, etc. Output device 370may include one or more mechanisms that output information to theoperator, including a display, a speaker, etc. Communicationinterface(s) 380 may include a transceiver that enables device 400 tocommunicate with other devices and/or systems. For example,communication interface(s) 380 may include a wired or wirelesstransceiver for communicating with transport nodes 120, possibly via anintervening network (not shown).

The configuration of components of device 300 illustrated in FIG. 3 isfor illustrative purposes only. Other configurations may be implemented.Therefore, device 300 may include additional, fewer and/or differentcomponents, or differently arranged components, from those depicted inFIG. 3.

FIG. 4 depicts a ROADM 135 according to an exemplary implementation. Inthe exemplary implementation of FIG. 4, ROADM 135 includes a WavelengthCrossconnect (WXC) type of ROADM. In other implementations, ROADM 135may include other types of ROADMs such as, for example, a PlanarLightwave Circuit (PLC) ROADM or a Wavelength Selective Switch (WSS)ROADM. The WXC type of ROADM depicted in FIG. 4 provides N×Nconnectivity. For a degree N−1 node and n wavelengths per fiber, the WXCtype of ROADM uses N demultiplexers, N Multiplexers, and n N×N switches.

ROADM 135 may include multiple optical demultiplexers 400-1 through400-N, multiple optical switches 410-1 through 410-n, and multipleoptical multiplexers 420-1 through 420-N.

Each of demultiplexers 400-1 through 400-N (generically referred toherein as a “demultiplexer 400”) receive optical signals carried bymultiple optical carriers (e.g., wavelengths λ₁ through λ_(n)) over anoptical fiber (as depicted by the bold arrows at the left-hand side ofFIG. 4). Demultiplexer 400 demultiplexes the multiple opticalwavelengths into single output wavelengths and outputs each wavelength λto its respective switch of switches 410-1 through 410-n. For example,demux 400-1 demultiplexes optical signals on each of wavelengths λ₁through λ_(n) and sends optical signals for wavelength λ₁ to switch410-1, optical signals for wavelength λ₂ to switch 410-2, etc.

Switches 410-1 through 410-n (generically and individually referred toherein as a “switch 410”) may receive optical signals carried on asingle optical wavelength from each of demuxes 400-1 through 400-N, andmay switch the optical signals to one of Multiplexers 420-1 through420-N based on switching control instructions. Each switch 410 operateson a single optical wavelength and switches optical signals carried onthat optical wavelength from any input port to any output port. Forexample, switch 410-1 may switch optical signals received on wavelengthλ₁ from demultiplexer 400-1 to multiplexer 420-N for output on anoptical fiber from ROADM 135. As another example, switch 410-4 mayswitch optical signals received on wavelength λ₄ from demultiplexer400-3 to multiplexer 420-1 for output on an optical fiber from ROADM135. Each of multiplexers 420-1 through 420-N (generically referred toherein as “multiplexer 420”) may multiplex optical signals carried onone or more different wavelengths, received from switches 410-1 through410-n, for output to an optical fiber.

The configuration of components of device ROADM 135 illustrated in FIG.4 is for illustrative purposes only. Other configurations may beimplemented. Therefore, ROADM 135 may include additional, fewer and/ordifferent components, or differently arranged components, than thosedepicted in FIG. 4. For example, ROADM 135 may alternatively include aPLC ROADM or a WSS ROADM.

FIGS. 5 and 6 depict examples of flexible channel coordination of theoptical transport nodes 120 of FIG. 2 during two different transportperiods. A “transport period,” as referred to herein includes a singlewindow of time, with each transport period succeeding one another. Eachtransport period may be a same length of time, or the length of eachtransport period may be controlled by systems 110 and/or 115. In FIG. 5,during a first transport period t₁, a selected first set 500 of multipleoptical carriers (e.g., wavelengths) are switched through ROADM A 135-Ato destination transport node 120-B; and a selected second set 510 ofthe multiple optical carriers (e.g., wavelengths) are switched throughROADM A 135-A to destination transport node 120-C. In FIG. 6, during asecond transport period t₂, a selected third set 600 of multiple opticalcarriers (e.g., wavelengths) are switched through ROADM A 135-A todestination transport node 120-B, and a selected fourth set 610 of themultiple optical carriers (e.g., wavelengths) are switched through ROADMA 135-A to destination transport node 120-C. As can be seen in FIG. 5,first set 500 of the multiple optical carriers includes wavelengths λ₁and λ₂, and second set 510 of the multiple optical carriers includeswavelengths λ₃ through λ_(n). As can be seen in FIG. 6, third set 600 ofthe multiple optical carriers includes wavelength λ₂, and fourth set 610of the multiple optical carriers includes wavelength and wavelengths λ₃through λ_(n).

Returning to FIG. 5, during transport period t₁, incoming data trafficis received at router A 125-A of transport node 120-A. Router A 125-A,using a routing algorithm and based on instructions received from routermanagement system 110, determines an outgoing client interface 140-A₁via which to send each data flow of the data traffic. A “data flow,” asdescribed herein, refers to a series of data units (e.g., data frames ordata packets) sent between a source and a destination during a givensession. Client interface 140-A₁ sends the data traffic, as opticalsignals via multiple optical carriers (e.g., wavelengths λ₁ throughλ_(n)), to a client interface 145-A₁ of transport equipment A 130-A.Client interface 145-A₁ converts the optical signals of the data trafficto electrical signals, and sends the data traffic as electrical signalsto transport card 150-A₁. Transport card 150-A₁ converts the datatraffic, as electrical signals, back to optical signals and sends theoptical signals via multiple optical carriers (e.g., wavelengths λ₁through λ_(n)) to ROADM A 135-A. ROADM A 135-A, during transport periodt₁ and based on switching control instructions from transport card/ROADMmanagement system 115, switches wavelengths λ₁ and λ₂ (as shown in FIG.5) for transport to destination transport node 120-B via one or moreoptical fibers connected to ROADM B 135-B, and switches wavelengths λ₃through λ_(n) (as shown in FIG. 6) for transport to destinationtransport node 120-C via one or more optical fibers connected to ROADM C135-C.

Referring to FIG. 6, during transport period t₂, incoming data trafficis received at router A 125-A of transport node 120-A. Router A 125-A,using a routing algorithm and based on additional instructions receivedfrom router management system 110, determines an outgoing clientinterface 140-A₁ via which to send each data flow of the data traffic.Client interface 140-A₁ sends the data traffic, as optical signals viamultiple optical carriers (e.g., wavelengths λ₁ through λ_(n)), to aclient interface 145-A₁ of transport equipment A 130-A. Client interface145-A₁ converts the optical signals of the data traffic to electricalsignals, and sends the data traffic as electrical signals to transportcard 150-A₁. Transport card 150-A₁ converts the data traffic, aselectrical signals, back to optical signals and sends the opticalsignals via multiple optical carriers (e.g., wavelengths λ₁ throughλ_(n)) to ROADM A 135-A. ROADM A 135-A, during transport period t₂ andbased on additional switching control instructions from transportcard/ROADM management system 115, switches wavelength 2 (as shown inFIG. 6) for transport to destination transport node 120-B via an opticalfiber connected to ROADM B 135-B, and switches wavelengths λ₁, and λ₃through λ_(n) (as shown in FIG. 6) for transport to destinationtransport node 120-C via one or more optical fibers connected to ROADM C135-C. The selective switching of different optical wavelengths todestination nodes may continue at each subsequent transport period basedon instructions generated by systems 110 and 115.

FIGS. 7A and 7B are flow diagrams that illustrate an exemplary processfor flexible channel coordination during optical transport in thenetwork environment 100 of FIG. 1. The exemplary process of FIGS. 7A and7B may be implemented by router management system 110 and transportcard/ROADM management system 115. The exemplary process of FIGS. 7A and7B is described below with reference to FIGS. 2, 5 and 6.

The exemplary process may include router management system 110 receivinga data traffic demand change request(s) (block 700). In someembodiments, data traffic demand change requests may be automaticallygenerated within network 105 based on a current traffic load at one ormore of the transport nodes of network 105. For example, a node innetwork 105 that monitors a current traffic load, and changes in datatraffic demand, may automatically generate a demand change request basedon the monitored current traffic load. In some embodiments, routermanagement system 110 may receive a data traffic demand change requestfrom one or more customers of optical network 105. The data trafficdemand change request from the one or more customers may be based on acustomer need for improved bandwidth, or a need for improvement in otherdata traffic delivery metrics.

Router management system 110 may assign a new data flow for each opticalcarrier (e.g., wavelength) of each multiple optical carrier (e.g.,multi-wavelength) client interface for a next transport period (block705). Router management system 110, therefore, identifies the dataflow(s) at each transport node 120, and assigns an optical carrier(e.g., wavelength), of multiple optical carriers, of an appropriateoutgoing client interface 140 of router 125 to each of the data flows.For example, when the multiple optical carriers include light ofmultiple different wavelengths, a first data flow may be assigned towavelength λ₁, and a second data flow may be assigned to wavelength λ₂.The outgoing interface 140 of router 125 may be determined based on arouting algorithm performed by router 125. In assigning the opticalwavelength to the data flow, router management system 110 coordinatesamong all of the data flows for a particular outgoing client interface140 of router 125.

Router management system 110 may notify transport card/ROADM managementsystem 115 of data flow changes in a next transport period (block 710).Based on the assignment of an optical carrier (e.g., wavelength), of themultiple optical carriers (e.g., multiple wavelengths), of an outgoingclient interface 140 of router 125 for each data flow, router managementsystem 110 notifies transport card/ROADM management system 115 of thedata flow changes and the corresponding optical carrier (e.g.,wavelength) assignments. Transport card/ROADM management system 115 mayassign new optical carrier configuration patterns (e.g., new wavelengthconfiguration patterns) to the transport cards and ROADMs for the nexttransport period (block 715). The notification from router managementsystem 110 includes data indicating an optical carrier (e.g.,wavelength) assigned to each data flow for a given client interface 140of router 125. For example, transport card/ROADM management system 115identifies the corresponding optical wavelength output from a transportcard 150 of transport equipment 130 and determines the switchingconfiguration of the ROADM 135 that is connected to the transportequipment 130 to connect the data flow's assigned optical wavelength ona switched path to the destination transport node 120 for the datatraffic corresponding to the particular data flow. Referring to theexample of FIG. 5, if a first data flow, destined for transport node120-B, has been assigned optical wavelength λ₁ during transport periodt₁, then transport card/ROADM management system 115 identifies the inputto ROADM A 135-A on wavelength λ₁ from transport card 150-A₁, anddetermines the switching configuration that switches that input to anoutput of ROAM A 135-A connected to an optical fiber that furtherconnects, either directly or indirectly via intervening nodes, todestination transport node 120-B. During transport period t₁, the firstdata flow may then be transported via optical signals of wavelength λ₁over the switched path (e.g., path including client interface 140-A₁,client interface 145-A₁, transport card 150-A₁, and switched paththrough ROADM A 135-A that connects λ₁ of transport card 150-A1 totransport node 120-B) of the switching configuration determined bytransport card/ROADM management system 115.

Referring to another example in FIG. 5, if a second data flow, destinedfor transport node 120-C, has been assigned optical wavelength λ₃ duringtransport period t₁, then transport card/ROADM management system 115identifies the input to ROADM A 135-A on wavelength λ₃ from transportcard 150-A₁, and switches that input to an output of ROADM A 135-Aconnected to an optical fiber that further connects, either directly orindirectly via intervening nodes, to destination transport node 120-C.During transport period t₁, the second data flow may then be transportedvia optical signals of wavelength λ₃ over the switched path (e.g., pathincluding client interface 140-A₁, client interface 145-A₁, transportcard 150-A₁, and switched path through ROADM A 135-A that connects λ₃ oftransport card 150-A1 to transport node 120-C) of the switchingconfiguration determined by transport card/ROADM management system 115.

Transport card/ROADM management system 115 may notify router managementsystem 110 that the transport layer is ready (block 720). Transportcard/ROADM management system 115 may send a notification message torouter management system 110 that includes data indicating that thewavelength configuration patterns for affected transport nodes is setfor a given transport period. Transport card/ROADM management system 115sets a reconfiguration time for routers 125, transport cards 150, andROADMs 135 (block 725). The reconfiguration time set by system 115 mayinvolve an estimate of the time required to make the data flow changesat client interfaces 140 of routers 125, and the changes in opticalcarrier configuration patterns (e.g., wavelength configuration patterns)at transport cards 150 and ROADMs 135, and when the next transportperiod shall begin. Transport card/ROADM management system 115 maynotify router management system 105 of the reconfiguration time and whenthe next transport period shall begin.

Router management system 110 determines if a next transport period isbeginning (block 730). Router management system 110 may keep track of acurrent transport period, when the current transport period ends, andwhen the next transport period begins based on the reconfiguration timenotification received from transport card/ROADM management system 115.If the next transport period has not yet begun (NO—block 730), thenblock 730 may repeat until the beginning of the next transport period.If a next transport period is beginning (YES—block 730), then routermanagement system 110 instructs the routers 125 to hold traffic on allrouter interfaces (block 735). Router management system 110 sends amessage to each router 125 of each transport node 120 instructing eachclient interface 140 to buffer all outgoing traffic.

Transport card/ROADM management system 115 instructs transport cards andROADMs to switch to the new configuration (block 740). Transportcard/ROADM management system 115 sends instructions to each transportcard 150 and ROADM 135 to switch to the new wavelength configurationpattern assigned in block 715. Transport card/ROADM management system115 notifies router management system 105 when the reconfiguration iscomplete (block 745). Once each transport card 150 and ROADM 135 hasswitched to the new optical carrier configuration pattern (e.g.,wavelength configuration pattern), transport card/ROADM managementsystem 115 sends a message to router management system 110 that thewavelength configuration pattern change is completed. Router managementsystem 110 instructs all involved routers to resume traffic flows (block750). Router management system 110 sends a message to each involvedrouter 125 to stop buffering data flows, and to begin transmitting thedata traffic of the data flows out assigned optical carriers (e.g.,wavelengths) of outgoing client interfaces 140.

Router management system 110 determines if there is a new data trafficdemand change (block 755). In some embodiments, new data traffic demandchange requests may be automatically generated within network 105 basedon a current traffic load at one or more of the transport nodes ofnetwork 105. For example, a node in network 105 that monitors a currenttraffic load, and changes in data traffic demand, may automaticallygenerate a demand change request based on the monitored current trafficload. In some embodiments, router management system 110 may receive anew data traffic demand change request from one or more customers. Thedata traffic demand change request from the one or more customers may bebased on a customer need for improved bandwidth, or a need forimprovement in other data traffic delivery metrics. If there is no newdata traffic demand change (NO—block 755), then the exemplary processloops at block 755 until a change in data traffic demand occurs. Ifthere is a new data traffic demand change (YES—block 755), then theexemplary process returns to block 700 with router management system 110receiving a data traffic demand change request.

FIGS. 8 and 9 depict examples of channel coordination among multipleoptical transport nodes during two different transport periods. FIGS. 8and 9 involve a specific example of a portion of optical network 105 inwhich transport nodes C1, C2, A1, A2 and A3 are interconnected, andchanges that occur in optical carrier configuration patterns (e.g.,wavelength configuration patterns) between the transport nodes over twotransport periods t₁ and t₂. In the examples of FIGS. 8 and 9, eachclient interface of routers 125, and each client interface and transportcard of transport equipment 130, handles eight optical carriers (e.g.,optical wavelengths λ₁ through λ₈).

As shown in FIG. 8, during transport period t₁, ROADM 135-C₁ and ROADM135-A₁ switch two optical wavelengths from a first transport card oftransport equipment 130-C₁ of transport node C1 to a first transportcard of transport equipment 130-A₁ of transport node A1. Additionally,during transport period t₁, ROADM 135-C₁ and ROADM 135-A₂ switch anothertwo optical wavelengths from the first transport card of transportequipment 130-C₁ of transport node C₁ to a transport card of transportequipment 130-A₂ of transport node A2.

Furthermore, during transport period t₁, ROADM 135-C₁ and ROADM 135-A₃switch 1 optical wavelength from a second transport card of transportequipment 130-C₁ of transport node C₁ to a transport card of transportequipment 130-A₃ of transport node A3. Also, during transport period t₁,ROADM 135-C₁ and ROADM 135-C₂ switch another three optical wavelengthsfrom the second transport card of transport equipment 130-C₁ oftransport node C1 to a second transport card of transport equipment130-C₂ of transport node C2.

FIG. 8 additionally depicts ROADM 135-A₁ and ROADM 135-C₂ switching,during transport period t₁, 3 optical wavelengths from a secondtransport card of transport equipment 130-A₁ of transport node A1 to afirst transport card of transport equipment 130-C₂ of transport node C2.As shown, ROADM 135-A₂ and ROADM 135-C₂ further, during transport periodt₁, switch 1 optical wavelength from the transport card of transportequipment 130-A₂ of transport node A2 to the first transport card oftransport equipment 130-C₂ of transport node C2. ROADM 135-A3 and ROADM135-C₂ further, during transport period t₁, switch 1 optical wavelengthfrom the transport card of transport equipment 130-A₃ of transport nodeA3 to the second transport card of transport equipment 130-C₂ oftransport node C2.

FIG. 9 depicts wavelength configuration pattern changes that occur amongthe transport nodes C1, C2, A1, A2 and A3 at the occurrence of transportperiod t₂. Transport nodes C1, C2, A1, A2 and A3 may receiveinstructions from transport card/ROADM management system 115 toinstitute the changes in wavelength configuration patterns based on, forexample, a change in data traffic demand in optical network 105.

As shown in FIG. 9, during transport period t₂, ROADM 135-C₁ and ROADM135-A₁ switch 1 optical wavelength from a first transport card oftransport equipment 130-C₁ of transport node C1 to a first transportcard of transport equipment 130-A₁ of transport node A1. Additionally,during transport period t₂, ROADM 135-C₁ and ROADM 135-A₂ switch anothertwo optical wavelengths from the first transport card of transportequipment 130-C₁ of transport node C₁ to a transport card of transportequipment 130-A₂ of transport node A2.

Furthermore, during transport period t₂, ROADM 135-C₁ and ROADM 135-A₃switch 3 optical wavelengths from a second transport card of transportequipment 130-C₁ of transport node C₁ to a transport card of transportequipment 130-A₃ of transport node A3. Also, during transport period t₂,ROADM 135-C₁ and ROADM 135-C₂ switch another single optical wavelengthfrom the second transport card of transport equipment 130-C₁ oftransport node C1 to a second transport card of transport equipment130-C₂ of transport node C2.

FIG. 9 additionally depicts ROADM 135-A₁ and ROADM 135-C₂ switching,during transport period t₂, 2 optical wavelengths from a secondtransport card of transport equipment 130-A₁ of transport node A1 to afirst transport card of transport equipment 130-C₂ of transport node C2.As shown, ROADM 135-A₂ and ROADM 135-C₂ further, during transport periodt₂, switch 2 optical wavelengths from the transport card of transportequipment 130-A₂ of transport node A2 to the first transport card oftransport equipment 130-C₂ of transport node C2.

ROADM 135-A3 and ROADM 135-C₂ further, during transport period t₂,switch 1 optical wavelength from the transport card of transportequipment 130-A₃ of transport node A3 to the second transport card oftransport equipment 130-C₂ of transport node C2.

At each transport period subsequent to transport periods t₁ and t₂ (notshown in FIGS. 8 and 9), transport card/ROADM management system 115 mayinstruct transport nodes C1, C2, A1, A2 and A3 to institute additionalchanges in wavelength configuration patterns to change which opticalwavelengths of wavelengths λ₁ through λ₈ are switched from a giventransport card of transport equipment 130 through a ROADM 135 to anothertransport equipment 130 via another ROADM 135.

The foregoing description of implementations provides illustration anddescription, but is not intended to be exhaustive or to limit theinvention to the precise form disclosed. Modifications and variationsare possible in light of the above teachings or may be acquired frompractice of the invention. For example, while a series of blocks hasbeen described with respect to FIGS. 7A and 7B, the order of the blocksmay be varied in other implementations. Moreover, non-dependent blocksmay be performed in parallel.

Certain features described above may be implemented as “logic” or a“unit” that performs one or more functions. This logic or unit mayinclude hardware, such as one or more processors, microprocessors,application specific integrated circuits, or field programmable gatearrays, software, or a combination of hardware and software.

No element, act, or instruction used in the description of the presentapplication should be construed as critical or essential to theinvention unless explicitly described as such. Also, as used herein, thearticle “a” is intended to include one or more items. Further, thephrase “based on” is intended to mean “based, at least in part, on”unless explicitly stated otherwise.

In the preceding specification, various preferred embodiments have beendescribed with reference to the accompanying drawings. It will, however,be evident that various modifications and changes may be made thereto,and additional embodiments may be implemented, without departing fromthe broader scope of the invention as set forth in the claims thatfollow. The specification and drawings are accordingly to be regarded inan illustrative rather than restrictive sense.

What is claimed is:
 1. A method, comprising coordinating, by one or moremanagement systems, a first wavelength configuration pattern of aplurality of multi-wavelength optical transport nodes in an opticalnetwork for a first transport period, wherein the first wavelengthconfiguration pattern comprises multiple optical wavelengths havingfirst switched paths through a first reconfigurable optical add/dropmultiplexer (ROADM) of the plurality of multi-wavelength opticaltransport nodes; determining, by the one or more management systems,data traffic demand changes in the optical network; and coordinating, bythe one or more management systems, a second wavelength configurationpattern of the plurality of multi-wavelength optical transport nodes inthe optical network for a second transport period that is subsequent tothe first transport period, based on the determined data traffic demandchanges.
 2. The method of claim 1, wherein the first switched pathsthrough the first ROADM comprise a first set of the multiple opticalwavelengths switched through the first ROADM to a first destination nodeand a second set of the multiple optical wavelengths switched throughthe first ROADM to a second destination node.
 3. The method of claim 2,wherein the second wavelength configuration pattern comprises the secondset of the multiple optical wavelengths having second switched pathsthrough the first ROADM, wherein the second switched paths are differentfrom the first switched paths.
 4. The method of claim 3, wherein thesecond switched paths through the first ROADM comprise a third set ofthe multiple optical wavelengths switched through the first ROADM to athird destination node and a fourth set of the multiple opticalwavelengths switched through the first ROADM to a fourth destinationnode.
 5. The method of claim 1, wherein coordinating the secondwavelength configuration pattern of the plurality of multi-wavelengthoptical transport nodes for the second transport period comprises:assigning a data flow for each wavelength of a plurality of opticalwavelengths associated with a client interface of an optical router; andinstructing a second ROADM to switch each wavelength of the plurality ofoptical wavelengths associated with one or more transport cards of oneof the plurality of multi-wavelength optical transport nodes to arespective destination transport node.
 6. The method of claim 1, whereineach of the plurality of multi-wavelength optical transport nodesincludes an optical router, an optical transport equipment, and at leastone of the first ROADM or another ROADM.
 7. The method of claim 1,further comprising: determining, by the one or more management systems,additional data traffic demand changes in the optical network; andcoordinating, by the one or more management systems, a third wavelengthconfiguration pattern of the plurality of multi-wavelength opticaltransport nodes in the optical network for a third transport period thatis subsequent to the second transport period, based on the determinedadditional data traffic demand changes.
 8. One or more systems,comprising one or more communication interfaces configured to couple,via a plurality of links, to a plurality of multi-wavelength opticaltransport nodes in an optical network; at least one processing unitconfigured to: coordinate a first wavelength configuration pattern of aplurality of multi-wavelength optical transport nodes in an opticalnetwork for a first transport period, wherein the first wavelengthconfiguration pattern comprises multiple optical wavelengths havingfirst switched paths through a first reconfigurable optical add/dropmultiplexer (ROADM) of the plurality of multi-wavelength opticaltransport nodes, determine data traffic demand changes in the opticalnetwork, and coordinate a second wavelength configuration pattern of theplurality of multi-wavelength optical transport nodes in the opticalnetwork for a second transport period that is subsequent to the firsttransport period, based on the determined data traffic demand changes.9. The one or more systems of claim 8, wherein the first switched pathsthrough the first ROADM comprise a first set of the multiple opticalwavelengths switched through the first ROADM to a first destination nodeand a second set of the multiple optical wavelengths switched throughthe first ROADM to a second destination node.
 10. The one or moresystems of claim 9, wherein the second wavelength configuration patterncomprises the second set of the multiple optical wavelengths havingsecond switched paths through the first ROADM, wherein the secondswitched paths are different from the first switched paths.
 11. The oneor more systems of claim 10, wherein the second switched paths throughthe first ROADM comprise a third set of the multiple optical wavelengthsswitched through the first ROADM to a third destination node and afourth set of the multiple optical wavelengths switched through thefirst ROADM to a fourth destination node.
 12. The one or more systems ofclaim 8, wherein, when coordinating the second wavelength configurationpattern of the plurality of multi-wavelength optical transport nodes forthe second transport period, the at least one processing unit isconfigured to: assign a data flow for each wavelength of a plurality ofoptical wavelengths associated with a client interface of an opticalrouter; and instruct a second ROADM to switch each wavelength of theplurality of optical wavelengths associated with one or more transportcards of one of the plurality of multi-wavelength optical transportnodes to a respective destination transport node.
 13. The one or moresystems of claim 8, wherein each of the plurality of multi-wavelengthoptical transport nodes includes an optical router, optical transportequipment, and at least one of the first ROADM or another ROADM.
 14. Theone or more systems of claim 8, wherein the at least one processing unitis further configured to: determine additional data traffic demandchanges in the optical network; and coordinate a third wavelengthconfiguration pattern of the plurality of multi-wavelength opticaltransport nodes in the optical network for a third transport period thatis subsequent to the second transport period, based on the determinedadditional data traffic demand changes.
 15. A non-transitorycomputer-readable medium including instructions, the one or moreinstructions comprising: one or more instructions that, when executed bya processor, cause the processor to: coordinate a first wavelengthconfiguration pattern of a plurality of multi-wavelength opticaltransport nodes in an optical network for a first transport period,wherein the first wavelength configuration pattern comprises multipleoptical wavelengths having first switched paths through a firstreconfigurable optical add/drop multiplexer (ROADM) of the plurality ofmulti-wavelength optical transport nodes, determine data traffic demandchanges in the optical network, and coordinate a second wavelengthconfiguration pattern of the plurality of multi-wavelength opticaltransport nodes in the optical network for a second transport periodthat is subsequent to the first transport period, based on thedetermined data traffic demand changes.
 16. The non-transitorycomputer-readable medium of claim 15, wherein the first switched pathsthrough the first ROADM comprise a first set of the multiple opticalwavelengths switched through the first ROADM to a first destination nodeand a second set of the multiple optical wavelengths switched throughthe first ROADM to a second destination node.
 17. The non-transitorycomputer-readable medium of claim 16, wherein the second wavelengthconfiguration pattern comprises the second set of the multiple opticalwavelengths having second switched paths through the first ROADM,wherein the second switched paths are different from the first switchedpaths.
 18. The non-transitory computer-readable medium of claim 17,wherein the second switched paths through the first ROADM comprise athird set of the multiple optical wavelengths switched through the firstROADM to a third destination node and a fourth set of the multipleoptical wavelengths switched through the first ROADM to a fourthdestination node.
 19. The non-transitory computer-readable medium ofclaim 15, wherein each of the plurality of multi-wavelength opticaltransport nodes includes an optical router, an optical transportequipment, and at least one of the first ROAD or another ROADM.
 20. Thenon-transitory computer-readable medium of claim 15, further comprisingone or more instructions that cause the processor to: determineadditional data traffic demand changes in the optical network; andcoordinate a third wavelength configuration pattern of the plurality ofmulti-wavelength optical transport nodes in the optical network for athird transport period that is subsequent to the second transportperiod, based on the determined additional data traffic demand changes.